Many ask what is appropriate for use in things destined for
liturgical service. The governing document for such items is the "General Instruction
of the Roman Missal."

Sacred Vessels

The 2002 GIRM gives the following guidance:

328. Sacred vessels are to be made from precious metal. If
they are made from metal that rusts or from a metal less
precious than gold, then ordinarily they should be gilded on
the inside.

329. In the Dioceses of the United States of America, sacred
vessels may also be made from other solid materials that,
according to the common estimation in each region, are
precious, for example, ebony or other hard woods, provided that
such materials are suited to sacred use and do not easily break
or deteriorate. This applies to all vessels which hold the
hosts, such as the paten, the ciborium, the pyx, the
monstrance, and other things of this kind.

330. As regards chalices and other vessels that are intended
to serve as receptacles for the Blood of the Lord, they are to
have bowls of nonabsorbent material. The base, on the other
hand, may be made of other solid and worthy materials.

331. For the consecration of hosts, a large paten may
appropriately be used; on it is placed the bread for the priest
and the deacon as well as for the other ministers and for the
faithful.

332. As to the form of the sacred vessels, the artist may
fashion them in a manner that is more in keeping with the
customs of each region, provided each vessel is suited to the
intended liturgical use and is clearly distinguishable from
those intended for everyday use.

The Congregation for Divine Worship elaborated in 1980 in its Instruction on Certain Norms concerning
the Worship of the Eucharistic Mystery (Inaestimabile donum), saying,

16. The form of the vessels must be appropriate for the
liturgical use for which they are meant. The material must be
noble, durable and in every case adapted for sacred use. In this
sphere judgment belongs to the Episcopal Conference of the
individual regions. Use is not to be made of simple baskets or
other receptacles, nor are the sacred vessels to be of poor
quality or lacking any artistic style.

Most recently, in 2004 the Congregation for Divine Worship,
addressing abuses in these matters (such as the use of glass
vessels), decreed in Redemptionis sacramentum,

117. Sacred vessels for containing the Body and Blood of the Lord
must be made in strict conformity with the norms of tradition and of
the liturgical books. The Bishops’ Conferences have the faculty to
decide whether it is appropriate, once their decisions have been
given the recognitio by the Apostolic See, for sacred vessels to be
made of other solid materials as well. It is strictly required,
however, that such materials be truly noble in the common estimation
within a given region, so that honour will be given to the Lord by
their use, and all risk of diminishing the doctrine of the Real
Presence of Christ in the Eucharistic species in the eyes of the
faithful will be avoided. Reprobated, therefore, is any practice
of using for the celebration of Mass common vessels, or others
lacking in quality, or devoid of all artistic merit or which are
mere containers, as also other vessels made from glass, earthenware,
clay, or other materials that break easily. This norm is to be
applied even as regards metals and other materials that easily rust
or deteriorate. [emphasis added]

Rome's purpose seems evident. In poorer countries it may be necessary to have
some latitude
owing to the cost and availability of the material. What is considered
noble in a region is fit for use in the liturgy, though the articles should be made for
sacred use and not be profane vessels pressed into sacred service.
It should be remembered, too, that among the saints, even those
like St. Jean Marie Vianney who was noteworthy for his personal simplicity
and evangelical poverty, there was never any skimping on the sacred
objects
used in the Divine Liturgy.

Vestments

In the matter of vestments the 2002 GIRM states,

343. In addition to the traditional materials, natural fabrics
proper to each region may be used for making sacred vestments;
artificial fabrics that are in keeping with the dignity of the
sacred action and the person wearing them may also be used. The
Conference of Bishops will be the judge in this matter.

344. It is fitting that the beauty and nobility of each
vestment derive not from abundance of overly lavish ornamentation,
but rather from the material that is used and from the design.
Ornamentation on vestments should, moreover, consist of figures,
that is, of images or symbols, that evoke sacred use, avoiding
thereby anything unbecoming.